1. Field of the Invention
The present invention relates to the sliding regulator of an operating unit, comprising a sliding slot with a rubbery-elastic sealing lip to prevent penetration of unwanted matter, e.g. dust, light or moisture. The sealing lip is arranged on the inside of the sliding regulator with respect to the operator remote side. A regulating member projects through the sliding slot and is movable along said slot.
2. Description of the Prior Art
Sliding regulators of this type include rotary regulators, as well as a number of alternative regulating means, and are widely used and known in engineering. Sliding regulators can be found, for example, in consumer electronics devices, in electric household appliances, and measuring devices and light dimmers. In most of these cases, sliding regulators are used to manually influence electrical values. In ventilation or air conditioning systems of motor vehicles, actuation of a sliding regulator opens or closes an element such as an air flap; additionally, if required, Bowden cables may be actuated.
According to the application or environment of the sliding regulator, it is generally useful to close the usually open sliding slot by a sealing means, so that the interior of the sliding regulator is protected against contaminants from the exterior, like dust and splash water etc., or to avoid penetration of light. In practice, sealing means of this kind can often be found in the form of screens or ribbon-type blinds, which move together with the regulating member. There are also sealing means covering the sliding slot of a sliding regulator, which are fixed, with the regulating members of the sliding regulator sliding along the sealing means and partially displacing it. An embodiment with a sealing means of this kind is disclosed in DE-U 87 08 331. In this embodiment, two rubber-elastic, fixed sealing lips, the sealing edges of which are directed against each other, overlap in the central area of the sliding slot. Upon actuation the regulating member slides along the sealing edges and partially opens the overlap.
The sealing means known in connection with sliding regulators have their respective specific advantages and disadvantages, e.g., with regard to cost of materials, expense for installing, required space, tightness etc., which will not be discussed here in great detail. However, in connection with stationary sealing means, it is noted that a brush-type embodiment is expensive to produce and at times light permeable, which is considered to be disadvantageous with internally arranged light sources. Similarly, a foil-type embodiment, due to its stretched position and/or rigidity, does not sit form-fit at the front faces of the sliding regulator in the moving direction, and allows formation of greater leaks.